The old fashioned Lobularia or Sweet Alyssum we planted 40 years ago was such a reliable and sweetly scented plant. Almost every seed from the packet would germinate at the front edge of the border. Later in the summer when the first plants were tired looking we would prune them back and find a dozen new seedlings coming up.
According to David Beaulieu, Alyssum's name comes from the Greek prefix a-and lyssa, rage. Alyssums were used in folk medicine where they were regarded as antidotes to rabies.
The photo you see here is a new hybrid from Proven Winners, called Snow Princess Lobularia Hybrid. The ones in my garden were sent to me as trial plants to see how they would do in our zone 7 heat and humidity. So far they are everything the publicity brags about.
The plant is sterile (grown from cuttings not from seed) so instead of making a dozen new plants from seed in the second half of the summer, it produces more and more flowers. Million Bells or Callbrachoa is the same - no pruning, just summer long bloom.
They are all members of the plant family, Brassicaceae so their relatives are mustards and cabbages of all kinds.
Look for Snow Princess in garden centers next spring. With growing habits like Million Bells, it should make a spectacular hanging basket plant.